算法题：名人问题，给出最优解法

 def findCelebrity(int n):
    celebrity = 0
    for i in range(1, n):
        if knows(celebrity, i):
            celebrity = i
    for i in range(n):
        if (celebrity != i and knows(celebrity, i)):
            return -1
        if (celebrity != i and !knows(i, celebrity)):
            return -1
    return celebrity

int findCelebrity(int n)
{
    if(n == 1) return 0;
    int cand = 0;          //假设名人为0
    for(int other = 1; other < n; ++other)
    {
        if(!know(other, cand) || know(cand, other))   //cand一定不是名人
            cand = other;
        else
            continue;
    }
    
    for(int i = 0; i < n; ++i)
    {
        if(cand == i)
            continue;
        if(know(cand, i) || !know(i, cand))
            return -1;
    }
    return cand;
}